2 files changed, 64 insertions, 0 deletions

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 6e6b6a11b3ce..b75d9fb2fa91 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -39,6 +39,19 @@ bool iommu_found(void)
 }
 EXPORT_SYMBOL_GPL(iommu_found);
 
+/**
+ * iommu_set_fault_handler() - set a fault handler for an iommu domain
+ * @domain: iommu domain
+ * @handler: fault handler
+ */
+void iommu_set_fault_handler(struct iommu_domain *domain,
+                                        iommu_fault_handler_t handler)
+{
+        BUG_ON(!domain);
+
+        domain->handler = handler;
+}
+
 struct iommu_domain *iommu_domain_alloc(void)
 {
         struct iommu_domain *domain;
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9940319d6f9d..d084e8777e0e 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -26,9 +26,18 @@
 #define IOMMU_CACHE     (4) /* DMA cache coherency */
 
 struct device;
+struct iommu_domain;
+
+/* iommu fault flags */
+#define IOMMU_FAULT_READ        0x0
+#define IOMMU_FAULT_WRITE       0x1
+
+typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
+                                struct device *, unsigned long, int);
 
 struct iommu_domain {
         void *priv;
+        iommu_fault_handler_t handler;
 };
 
 #define IOMMU_CAP_CACHE_COHERENCY       0x1
@@ -67,6 +76,43 @@ extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
                                       unsigned long iova);
 extern int iommu_domain_has_cap(struct iommu_domain *domain,
                                 unsigned long cap);
+extern void iommu_set_fault_handler(struct iommu_domain *domain,
+                                        iommu_fault_handler_t handler);
+
+/**
+ * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework
+ * @domain: the iommu domain where the fault has happened
+ * @dev: the device where the fault has happened
+ * @iova: the faulting address
+ * @flags: mmu fault flags (e.g. IOMMU_FAULT_READ/IOMMU_FAULT_WRITE/...)
+ *
+ * This function should be called by the low-level IOMMU implementations
+ * whenever IOMMU faults happen, to allow high-level users, that are
+ * interested in such events, to know about them.
+ *
+ * This event may be useful for several possible use cases:
+ * - mere logging of the event
+ * - dynamic TLB/PTE loading
+ * - if restarting of the faulting device is required
+ *
+ * Returns 0 on success and an appropriate error code otherwise (if dynamic
+ * PTE/TLB loading will one day be supported, implementations will be able
+ * to tell whether it succeeded or not according to this return value).
+ */
+static inline int report_iommu_fault(struct iommu_domain *domain,
+                struct device *dev, unsigned long iova, int flags)
+{
+        int ret = 0;
+
+        /*
+         * if upper layers showed interest and installed a fault handler,
+         * invoke it.
+         */
+        if (domain->handler)
+                ret = domain->handler(domain, dev, iova, flags);
+
+        return ret;
+}
 
 #else /* CONFIG_IOMMU_API */
 
@@ -123,6 +169,11 @@ static inline int domain_has_cap(struct iommu_domain *domain,
         return 0;
 }
 
+static inline void iommu_set_fault_handler(struct iommu_domain *domain,
+                                        iommu_fault_handler_t handler)
+{
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 #endif /* __LINUX_IOMMU_H */